title: A novel human T cell antigen preferentially expressed on mature T cells and shared by both well and poorly differentiated B cell leukemias and lymphomas.
abstract: A new lymphocyte differentiation antigen shared by all normal T cells and some malignant B cells was defined by a monoclonal antibody designated 12.1. This antibody reacted with all peripheral blood T cells but not with normal B cells and B cell lines. Analysis with a fluorescence activated cell sorter showed that the expression of 12.1 antigen changes during T cell maturation. Most thymocytes, blasts of acute T cell leukemia, and cells from established leukemic T cell lines bear a small amount of 12.1 antigen. In contrast the majority of peripheral blood T cells, activated T cells, and leukemic T cells of the Sezary syndrome bear a large amount of 12.1 antigen. Unexpectedly, antibody 12.1 reacted with leukemic cells from most patients with B-type chronic lymphocytic leukemia (CLL) and some patients with lymphosarcoma cell leukemia (LSCL). Among these leukemias, expression of the 12.1 antigen was not correlated with the stage of B cell maturation, with the amount of surface immunoglobulin on the cells, or with the presence or absence of monoclonal gammapathy. In a comparative serologic analysis the antigen defined by antibody 12.1 was distinct from the p67 T cell antigen (defined by monoclonal antibody 10.2) that is also known to be expressed by B-type CLL cells.
mesh_terms: D000208:Acute Disease; D000818:Animals; D000906:Antibodies; D000911:Antibodies, Monoclonal; D000921:Antibody-Producing Cells / Q000276:immunology; D000951:Antigens, Neoplasm; D001402:B-Lymphocytes / Q000276:immunology*; D002469:Cell Separation; D002999:Clone Cells / Q000276:immunology; D006801:Humans; D007938:Leukemia / Q000276:immunology*; D007945:Leukemia, Lymphoid / Q000276:immunology; D008223:Lymphoma / Q000276:immunology; D008228:Lymphoma, Non-Hodgkin / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D012751:Sezary Syndrome / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000906:Antibodies; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm